`markdown-heading-first`

No content appears between preamble and first heading.

Examples

error[markdown-heading-first]: Nothing is permitted between the preamble and the first heading
  --> input.md
   |
12 | This proposal describes the introduction in clients of a controlled gas limit increase strategy to determine the gas limit of a spec...
   |

Explanation

markdown-heading-first ensures that no content appears before the first heading.

It is improper form to put text/markdown outside of a section. Such text cannot be referred to in a URL (eg. #Section-Title), nor does it appear in the table of contents.